I'm with Amy -- just a little while but overall well satisfied. The bandwidth is what I needed, not the price although that's a real plus. No, neither I nor my users will ever suck down that much bandwidth but I can COMMIT it to them. They're all going to be the next Amazondotcom, you know.
Amy is responsive and pays attention to her people. There's a variety of ways to reach her. I don't know where she is (servers are Back East) but I've traded email with her long past midnight MST. Downtime has been negligible (maintenance only) and server response is plenty fast enough to satisfy me. I don't have a statistic to toss out because, frankly, I haven't had any reason to measure it.
Just for the record: I also have accounts elsewhere, one at a highly rated UK company that's well-thought of in WHT forums, and I find Estarr's performance every bit as stable and support just as good as the best. Estarr is new, that's all. Like they say: the price will attract business, the service will keep it. Besides, I can buy a couple of month's worth for cheap and try it out before I commit customers. Put some domains on, take them off, mount some PHP and see how it flys. I think she's still got a half-price special going on.